“The third way” in intrasaccular aneurysm treatment demonstrates positive one-year outcomes

galaxy seal device
Boris Pabon presenting at BRAIN 2023

A device labelled “the third way” to potentially treat intracranial aneurysms via an intrasaccular approach has demonstrated positive effectiveness and safety results at one year in a first-in-human (FIH) study, as per a presentation at the Barts Research and Advanced Interventional Neuroradiology (BRAIN) conference (4–6 December 2023, London, UK).

On the opening day of the conference, Boris Pabon (AngioTeam, Medellin, Colombia) shared one-year follow-up data from the PRE-SEAL IT trial, which is being conducted to assess the feasibility, effectiveness and safety of the novel Saccular Endovascular Aneurysm Lattice (SEAL) embolisation system (Galaxy Therapeutics).

“This kind of innovation is designed for those interventionists who are dissatisfied with the current intrasaccular technologies,” Pabon added, also detailing that the SEAL device is made from nitinol and has a dual-braided structure, offering a high mesh density at the level of the neck.

Pabon initially averred that, in wide-neck bifurcation aneurysms, coiling rates are currently going down, with usage of flow diverters and intrasaccular systems increasing—but that, “probably, no one […] has the right answer” when it comes to the best tool for treating these cases. Two key technologies exist right now in the intrasaccular space: Woven EndoBridge (WEB; Microvention/Terumo) and, more recently introduced, Contour (Cerus/Stryker).

“I think we have a gap, in terms of effectiveness between intrasaccular technologies and endoluminal technologies, and this gap represents a true opportunity—an opportunity that requires movement,” Pabon stated. “We really need something new. But, not just new. We need something different, and better, that helps us to reduce this gap.”

This was the context within which the Galaxy team began to conceptualise and develop its SEAL technology. Recounting an “exciting conversation” that took place back in 2021 with Osama Zaidat (Mercy Health, Toledo, USA)—now president and chief executive officer of Galaxy—Pabon recalled thinking: “Wow, I really want to be a part of this!” He also briefly outlined the device’s journey from being “a drawing on a napkin” to benchtop testing, animal models, and finally the FIH PRE-SEAL IT trial that started in early 2022.

The primary endpoints of the PRE-SEAL IT trial were feasibility, as per technical procedural success; effectiveness, as per complete occlusion rates; and safety outcomes. The trial was conducted in Medellin, Colombia, and saw a total of 33 non-consecutive, “highly selected” intracranial aneurysms treated across 29 patients. The majority of these aneurysms were located in the anterior circulation, and the “vast majority” were electively treated, Pabon detailed. Both configurations of the device—the SEAL Arc, designed to treat elongated, deep, saccular aneurysms, and the SEAL Base, better suited for irregular-shaped, shallow, non-saccular aneurysms—were used in the trial.

Arriving at PRE-SEAL IT’s key results, Pabon reported a technical success rate of 100%, with most of the cases—all but 10—being performed “without previous medication”. In addition, he relayed that no adjunctive therapies, such as assistive stents or balloons, were required in any of the cases.

Pabon went on to note that complete occlusion was achieved “immediately” after deployment in 20% of cases, and adequate occlusion was accomplished in two thirds of cases at the same timepoint. Twenty-four hours later, the investigators observed complete and adequate occlusion rates of 51.5% and 72.2%, respectively. And, at six months, they found that progressive complete occlusion had been reached in roughly 73% of cases, while adequate occlusion rates were closer to 90%.

“But, most importantly, at the one-year follow-up—in 26 of the 33 aneurysms [78.7%] in the series for which we had angiographic [data]—the complete occlusion rate was 76.9%, and adequate occlusion was seen in 84.6% of the cases,” Pabon said, also detailing that the PRE-SEAL IT investigators are expecting to have one-year follow-up data on all the aneurysms treated in the trial by early 2024. The presenter further noted, at one year, regrowth occurred in two aneurysms (8%), while all 29 patients (100%) with clinical follow-up data achieved a modified Rankin scale (mRS) score of 0–2.

Here, Pabon also posited that the complete occlusion outcome seen here provides evidence of a superior occlusion rate compared to the “famous number” of 50–60% typically reported with other intrasaccular technologies.

Regarding safety outcomes, Pabon stated that there were no haemorrhagic adverse events, including instances of ‘re-bleeding’; minor and transient thromboembolic adverse events were seen in three of the 33 treated patients (9%); and no major or definitive thromboembolic adverse events, nor definitive morbidities or procedural mortalities, were observed.

Pabon concluded his presentation by noting that, within these one-year experiences, the SEAL appears to be a feasible treatment option for intracranial aneurysms owing to its technical success rate of 100%. Furthermore, the device demonstrated effectiveness, via a 76.9% rate of progressive complete occlusion at one year, and a “really good safety profile”, with no observed morbidity or mortality, and a 0% retreatment rate.

In addition, the presenter speculated that the SEAL device may offer a “good solution” across a range of challenging scenarios—including in aneurysms that are ruptured, shallow, or greater than 10mm in size, but also as a means for avoiding dual antiplatelet therapy in some “highly selected” sidewall aneurysms.


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